#233F99
Closest named color: Cobalt (#1E488F). oklch(40.5% 0.151 266.4), rgb(35, 63, 153).
Aa
White text reads best on this color (9.36:1).
About this color
#233F99 is a dark, vivid blue. In OKLCH its lightness is 40%, its chroma 0.151 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.030 away. White text reads best on it, at 9.36:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | vivid (0.151) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.24:1 |
| White text | 9.36:1 |
Values
| HEX | #233F99 |
| RGB | rgb(35, 63, 153) |
| HSL | hsl(226, 63%, 37%) |
| OKLCH | oklch(40.5% 0.151 266.4) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #233F99 | 9.36:1 | AAA | Lc -95.5 | Preferred for body text |
| Black text on #233F99 | 2.24:1 | Fails | Lc 12.8 | Not readable |
| #233F99 text on white | 9.36:1 | AAA | Lc 91.1 | Preferred for body text |
| #233F99 text on black | 2.24:1 | Fails | Lc -11.2 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 800.
-
Step 50
50
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E2EAFC
oklch(93.6% 0.026 266.6)
-
Step 200
200
#CAD9FB
oklch(88.5% 0.05 266.5)
-
Step 300
300
#A6C0FB
oklch(81% 0.089 266)
-
Step 400
400
#789CF8
oklch(70.6% 0.141 266.7)
-
Step 500
500
#5781F5
oklch(63.2% 0.18 266.4)
-
Step 600
600
#3E67E4
oklch(55.7% 0.195 266.3)
-
Step 700
700
#3154C6
oklch(49.1% 0.182 266.5)
-
Step 800
800 (this color)
#233F99
oklch(40.5% 0.151 266.4)
-
Step 900
900
#243C7F
oklch(37.7% 0.117 266.1)
-
Step 950
950
#15244A
oklch(27% 0.073 265.6)
#233F99 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #004C9C | 0.035 |
| Deuteranopia (no green cones) | #004197 | 0.021 |
| Tritanopia (no blue cones) | #005665 | 0.121 |
| Achromatopsia (no color) | #464646 | 0.151 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #233F99
#233F99
oklch(40.5% 0.151 266.4)
- #5C4500
#5C4500
oklch(40.4% 0.083 86.9)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #233F99, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.030
- Sapphire #2138AB ΔE 0.034
- Blueberry #464196 ΔE 0.048
- Dark Slate Blue #483D8B ΔE 0.055
- Twilight Blue #0A437A ΔE 0.057
- Dusk Blue #26538D ΔE 0.061
- Light Navy #155084 ΔE 0.062
- Deep Sea Blue #015482 ΔE 0.075
Use #233F99 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.